Virkkunen and Colleagues (1989) The Virkkunen et al. (1989a) sample consisted of 58 Finnish men, 36 of whom had attempted or committed manslaughter and 22 of whom had committed arson. The researchers classified these crimes as impulsive or nonimpulsive (24 of the manslaughter crimes and all of the arson crimes were classified as impulsive). Data about each subject included age, Wechsler IQ, DSM-III scores, and abuse of alcohol. The researchers were especially interested in the predictive power of the concentration of 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF) and of a low blood glucose nadir.¹³ These variables were measured prior to the subject's release.

The follow-up period lasted 35.6 ± 18.0 months. (No explanation was provided for the variable length of the follow-up.) The Finnish Criminal Register was used to identify crimes during this period. Based on police reports, court documents, and hospital records, recidivism was defined as a new violent offense or arson.

A stepwise linear discriminate analysis was used to distinguish between recidivists (13 of 58) and nonrecidivists. The blood glucose nadir entered the model first, followed by the CSF 5-HIAA. (The researchers found no correlation between repeated violence and age or IQ, nor did these variables enter the analysis.) Using the model including both physiological variables, the group predicted to be violent had six recidivists and two nonrecidivists. The group predicted to be nonviolent had 42 nonrecidivists and 10 recidivists. The authors do not report their model's accuracy when the discriminate function is used to predict 13 recidivists (rather than the total number observed in the sample).

Virkkunen et al. (1989b:603) conclude that "the psychobiological variables as such or in combination with the behavioral variables had more predictive power for the outcome than any combination of behavioral variables." Also, consistent with the low blood glucose nadir, the researchers observed that without exception these offenders committed their crimes while under the influence of alcohol.

Black and Spinks (1985) Black and Spinks analyzed recidivism for assault during a five-year follow-up period for 125 men who were discharged into the community from Broadmore hospital (England) between 1960 and 1965. Broadmore is one of five hospitals in Great Britain for mentally disordered offenders. "In general, offender-patients have committed the kinds of offenses from which it is deemed the public need protection, and the hospital order reflects the acceptance by the court that there is some psychiatric